Ellipsograph



1,626,430 April Zini, 1927. A. C. SANDERS ELLIPSOGRAPH Filed May 25, 1925 K 2 Sheets-Sheet l INVENTOR 6 y flande ATTORNEYS WITNESSES April 26 1927. 156263430 A. C. SANDERS ELLIPSOGRAPH Filed May 25, 1925 2 sheets-sheet 2 Patented Apr. 26, i927.

UNITED STATES i ALLEN CAMPELL SANDERS, oE EEIE, PENNSYLVANIAI l Enmrsoonarn.

-ApplicationI led May 25, 1925. Serial No. 32,879.

This invention relates to improvements in drawing instrumentsand it consists of the constructions, combinations and arrangements herein described and claimed.

An object of the intention is to provide acompass by means lof which ellipses and ovals of various sizes and 'proportions can be drawn or inscribed in an expeditious and accurate manner.

Another object of the invention is to provide an ellipsograph which, having been adjusted tothe )yo dimensions along the minor and major (axes of the intended ellipse, can with oner` Continuous 1 51,. su chellipse accurately.

Other objects and advantages will appear in the following specification, `iefeierice being had to the accompanying drawings, in which- Figure 1 is a. perspective view of the'iinproved ellipsograph, illustrating the initial act of setting the pen at a along the minor axis of' the intended ellipse.

Figure 2 is an elevation thereof.

Figure 3 is another elevation showing how the pivot leg may be leaned over so that the drawing pen may touch the paper.

Figure 4 is a detail section on the line 4-4 of Figure 8.

Figure 5 is a perspective view illustrating the second actin adjusting the ellipsograph along the major axis of the intended ellipse until the drawing en touches the point b.

Figure 6 is a retail sectional view substantially on the line 6-6 of Figure 5.

Figure 7 is a detail sectional view of the improved pivot foot.

Figure 8 is a diagram illustrating various -kinds of ellipses or ovals actually drawn by the instrument. v

The general appearance of the improved drawing instrument is that of an ordinary compass for drawing pencil or ink line circles, and true to its similarity with the ordinary compass the improved instrument has ivot and drawinglegs 1 and 2, sol called ecause of their respective functions. The drawing pen 3 is removable from the drawing leg by means of the set lscrew 4, and is replaceable by a pencil point or other appropriate instrument with which the desired inscription is to be made.

Unlike the ordinary compass the pivot leg 1 does not turn about its axis. It is provided with a foot 5 with three points 6 which are intended to pierce the drawing surface turn be made to .draw

turning ofthe pivot leg as stated Itis upon this foot that the instrument can be either rocked or swayed sidewise upon the points 6 and lengthwise upon the bearing furnished by thesemi-circulai et e 7 and the corresponding semi-circular recess 8 in .the enlargement 9. -The arrangement permits the free oscillation of the pivot leg without turning, the center line or axis of the leg always pointing exactly to the center of the drawing area.

to prevent the.

The pivotv foot 5 is retained by means inl cluding a screw 10 (Fig. 7).

The. upper end of the pivot leg 1 terminates in a head l1 which carries a pair of rollers 12. The axes 13 (Fig. 4) of the rollers extend at right anglesV to the axis of the screw 10. The lturning plane of the rollers 12 1s at right angles to the plane in which the pivot leg l is capable of swinging in respect to the pivot foot 5. The latter-'direction of swinging is from rightl to left in Figs. 1 and 2. A stem 14 is pivoted at 15 in the liead 11. The Stem passes through a slot 16 in a disk 17 which is revoluble upon the rollers 12, and it is not untill the disk 17 has been turned sufficiently to dispose the slot 16 parallel with the axes 13 of the rollers that' the stem can be rocked or tilted upon its pivot (Figs. 5 and 6).

T he stein 14 passes through the central projection 18 of the handle yoke 19. handle 'oke is i'evoluble upon the stem, continuous y when the instrument is in use to draw an ellipse. -But the stem 14 will rock upon its pivot 15 only in the event that it is adjusted out of coaxial alignment with the pivot leg 1 whereupon it partakes of a rocking motion consonant with the revolution of the disk 17. i

The revoluble disk 17 has a pair of dia1netrically opposite ears 20 into which pivots 21 are fastened by screw threads or otherwise. Screws are preferable because they permit tightening. The yoke 22 of the drawing leg 2 is mounted upon the pivot screws 21. lVashers l2?) are interposed between the screw head, liandleyoke and draw-ing yoke 22 on each side. The pivot screws provide a. fricf tional mounting of the drawing yoke 22 u on the handle yoke 19, permitting indepen ent adjustment of the drawing leg as when setting the drawing pen 3 to the lesser dimension of the intended ellipse as atthe point a in Figure 1. This particular adjustment is independent of all other functions,

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A frictional-mounting for the handle yoke 19 upon the ears 20 of therevoluble disk 17 is also afforded by the pivot screws 21 so for the greater dimension of the intended el lipse as when the drawing pen is made to touch the point b in Figure '5. The rst adjustment is made of the drawing yoke in respect to the handle yoke, but the second adjustment is made of the handle yoke 1n respect to the revoluble disk.

A sleeve 24 constitutes that part of the handle which taken in the fingers of the operator to revolve the compass according to custom. The sleeve is tubular-and lits upon a tubular collar 25 upon the stem 14. The extremity of the stem is threaded at 26 to carry a' nut 27 by means of which the tension of a spring 28 may be regulated. The spring, being disposed between the collar 25 and nut 27 exerts pressure upon the revoluble v disk 17 to keep it in firm Contact with the rollers 12. Turning of the sleeve 24 causes turning of the yoke 19 by rneans of a sultable connection between the two, for example lugs 29 which fit in recesses 30.

1n order to insure holding the relative adjustment of the handle and yoke 19 in respect to the revoluble disk 17 when drawing ellipses, the disk is rovided with a' semi-circular plate 31 againstwhich a set screw 32 can be made to bear. The Vset screw is carried by an enlargement 33 on the underside of the yoke 19. I

To use the instrument the points 6 of the pivot foot 5 are set upon the major axis C of the intended ellipse, the central point coinciding with the intersection of the minor' axis I). The' point pricks are indicated at 34 in Figure 8. With the linger and thumb the operator grasps the drawing leg 2 and pulls it in the direction of the minor axis until the pen point registers with the mark a of the intended ellipse (Fig. 1). The compass is now swung around o and upon grasping the handle sleeve the yoke 19 is bowed over (Fig. 5) until the pen point 3 touches the mark b on the major axis. The instrument is now set to drafw the intended ellipse.

To draw the ellipse the draftsman may begin at the point a and swing the compass by twirling the handle sleeve 24v between the finger and thumb as with an ordinary compass, leaning the instrument toward the drawlng point or pen 3 and keeping an even pressure thereof upon the drawing paper. The ellipse is drawn with a continuous motion. it being unnecessary to lift the drawing pen from the paper until the ellipse is completed. The ellipse 35 (Fig. 8) is an example. To draw anrellipse of the same width as the ellipse 35, but with a' different.

lipses, but differs therefrom by being long and narrow. The instrument isicapable of drawing even narrower ellipses, and when used with the stem14 in line with the axis ot' the pivot leg- 1 (or in the exact center of the revoluble disk 17) will draw perfect circles.

The operation may be briefly described so that the reader may visualize the working of the compass. It is rea'dily seen that the pivot leg l is'rendered stationary, so far as turning movement is concerned, by impressing the three points `6 `into the pa 3er. Any twirling or twisting of the handle 24 will turn the handle yoke 19, the two being connected and result in the revolution of the disk 17 upon the rollers 12 of the pivot leg. The drawing pen 3 is carried by the revoluble disk, and as long as the stem 14 remains coa'xial with lthe pivot leg 1, the revolution of the disk 17 will result in the drawing of a circle by the pen point. The disk -17 then revolves in a plane at right angles to the axis of the pivot leg.) Y l Upon bending back upon the handle as in making the adjustment for the dimension of the ellipse along the major. axis (Figs. 5 and 6) the stem 14 (Figs. 4 and 6) is turned upon its pivot 15 so that it no longer assumes the coaxial relationship with the pivot leg 1. When the handle is now twirled to draw the ellipse there occurs a relative motion of the stem 14 and disk 17. The stem 14 rocks from side to side upon its pivot, the degree of rocking motion depending on the extent that it has been adjusted out of alignment with the pivot leg. The disk 17 instead of revolving in the former horizontal plane nowpartakes of an eccentric revoluble' motion from front to rear of the pivot leg, the degree ofeccentric motion of the disk being determined by the angularity of-the stem 14, but in all cases the relative motions of the parts are symmetrical.

The action is best understood by keeping in mind that a twirling effort upon the handle 24 must be distributed to the parts directly connectedto it. Such twirling effort will turn the stem 14, but by virtue of its a-ngularity (Fig. 6) the twirling motion will be resolved in a side to side -rocking motion of the stem upon the pivot 15.y As long as the handle assumes the angularity in Figure 6 theI revoluble disk will be found in the horizontal plane on top of the rollers 12. Asfsoon as the handle' has lrocked into colin:

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axial alignment with the pivot leg 1 (due other side of the pivot leg as shown in dotted lines in Figure 6, it being borne 1n mind that any adjusted'relationship of the handle andyoke 19 with the revoluble disk is preserved both by the frictional engagement at the pivots 2l and by the set screw 32. 'lhe resulting action is an eccentric or oscillating motion of the revoluble disk upon the rollers 12 accompanied by avrocking back and forth of the handle sleeve 24. This motion accompanies the drawing of the ellipse for which the instrument has been adjusted.

rl`he advantages may be briefly reviewed. The instrument performs as does an ordinary compass to produce a perfect circle of any diameter within the range of the instrument, without making any adjustment but supposing the handle stein 14 to be coaxial with the pivot leg 1, as already stated.

It performs as does an ordinary compass with two legs, one constituting the pivot, the other the drawing, cutting, marking or scratching implement. From the position assumed by the instrument in ordinary drawing, it can be said to draw an ellipse or oval of any proportions. The pivot foot contains three points 6 which pierce the draw.

ing paper and prevent the pivot leg 1 from turning as ordinarily. It is upon this foot that the instrument can be rocked sidewise either u on its points 6 or upon its semi-circular e ge 7, allowing it to sway or'oscillate without turning and always keeping the center line of the leg pointing exactly to the center of the drawing area.

It has been noted that the handle yoke-is capable of adjustment in respect to the revoluble disk 17 only when the part 16 has been turned around at right angles to the pivot 15 of the handle stem 14. It would be impossible to bend the handle in any direction when positioned as in Figure 1 because the sides of the-slot prevent rocking upon the pivot in the direction of the major axis and the pivot 15 itself prevents rocking of the handle in the direction of the minor axis. The disk 17 provides a path on which rollers 12 travel.

In drawing al circle, ellipse or oval the pen point 3 remains in the proper drawing position in respect to the line that it is producing. The pen point is not pushed into an improper drawing position as is usually the case with other instruments for drawing ellipses or ovals.

The instrument need not be operated in an upright position but can be leaned in any manner as an ordinary compass. In fact it operates like an ordinary compass with the added advantage of being adjustable to draw an ellipse or oval. The instrument permits drawing of an elliptical ligure by continuously marking the line outside lof the arca covered by the instrument. Other instruments require drawing within themselves or permit drawing only part of' an ellipse before they are required to be turned in an opposite or some other direction to complete the ellipse.

l claimzv l. An instrument of the character described comprising a non-revoluble pivot leg, a scriber carried thereby, means including a. disk which is revoluble upon the pivot leg, a pivot by which the stem is connected with the pivot leg whereby-the stem is adjtntable in respect to the disk and pivot leg, said stem when coaxial with the pivot leg causing the disk to revolve in a plane lat right angles to the axis of the leg but when tilted upon its pivot causes the disk to revolve with lan oscillatory movement in respec-t to the pivot leg of a degree determined bythe angularity of' the stem, and means 'to connect the scriber to the disk so as to move the scriber in consonance with the combined motion of the stem and disk thereby inscribing an ellipse.

2. An instrument of the character .described comprising a non-revoluble pivot leg, a drawing leg having a scriber, means carrying the drawing leg and being revoluble in a plane at right angles to the axis of the pivot leg thereby to describe a circle, and means pivoted on said pivot leg and associated with said revoluble means forrocking said revoluble lneans in respect to said right angular plane thereby distorting the'motion of the drawing leg about the pivot leg to describe an ellipse.

3. An instrument of the character described comprising a non-revoluble pivot leg, a drawing leg having a scriber, a disk carrying the drawing leg, and means having common frictional connection with said disk .and drawin leg and freel pivotal connection with said pivot leg, sai last means and said disk being adjustable relatively to each other to cause revolution of the disk in a horizontal plane when held at right angles to the pivot leg thereby causing the description of a circle or to revolve with-an oscillating motion in respect to the pivot leg to a degree determined by the angularity of adjustment of said means in respect to the pivot leg thereby cause said drawing leg to describe an ellipse.

4. An instrument of the character described comprising a non-revoluble pivot leg, a drawing leg having a scriber, a disk, andv means pivotally associated both with the pivot leg and the disk and whereby the 'drawing le is connected to the disk at one of said ivotal mountings, said means being adjusta le in respect to the pivot leg at its other pivotal mounting thereby to cause an oscillating motion of the disk and a rocking lll) motion of Vsaid means in respect tothe pivot leg axis resulting in the description of an lelliptical outline upon operation of the instrument.

5. An instrument f of the character described comprising a non-revoluble pivot leg,

. a dra-wing leg having a scriber and a yoke, a disk, a stem pivoted upon the pivot leg, a

handle incl-uding a yoke which is revoluble upon the stem, and a common, frictional pivotal connection between the drawing yoke, handle yoke and disk permitting a single adjustment of the drawing leg and yoke in re' spect to the handle yoke and disk to determine a measurement along the minor axis of an inten-ded ellipse, and permitting a com'- posite adjustment of the drawing and handle yoke in respect to the disk to determine a measurement along the major axis of the intended ellipse, the rocking of the stem upon its pivotal mounting being consonant with the last adjustment and determining the degree of oscillation of said disk upon revolution Vto make said ellipse.

6. An instrument of the character described comprising a non-revoluble pivot leg,

a drawing leg having a scriber and a yoke,

i a. stem pivoted upon the pivot leg, a handle including a yoke journaled upon the stem, a disk, and pivots providing a common frictional connection between the drawing and handle yokes and the disk, said disk being in horizontal alignment with the stem pivot when the stem is coaxial with the pivot leg,

i thereby permitting uniform revolution of the disk in a plane at right angles to the pivot leg axis, but periodically departing from said alignment when the stem is adjusted upon its pivot at an angleV to the pivot leg axis, thereby causing an oscillation of said disk in respect to the pivot leg during revolution. Y v

1,626,430 7. An instrument of the character described comprising a pivot leg having a head,

roller vbearings on the head, a stem pivoted uponthephead on an axis in line with but normal `to the axis of said roller bearings, a drawing leg having a yoke, a handle including a yoke having a projection journaled i' upon the stem, a disk revoluble upon the roller 'bearings and upon said stem having ears,- pvots frictionally connecting said drawing and handle yokes to the ears, said handle yoke and stem being in alignment, i

Vand a pivotal connection with said pivot leg and means to ix said adjustment including a plate carried by the disk and a screw associated with said yoke.

9. An instrument of the character described comprising a non-revoluble pivot leg, a disk, a scriber connected to the disk 'so as to revolve therewith about the axis of the pivot leg, a handle yoke pivotally connected to the disk and by which revolu tion 1s imparted to the`disk, a stem pivotally carried by the pivot leg upon which l the handle yoke and disk are revoluble, and a sleeve itted upon the stem to be manipulated by the fingers of the operator, said sleeve being connected with the handle yoke by means of lugs and recesses.

ALLEN CAMPELL SANDERS. 

